Heat exchange equipment



Dec. 15, 1959 E CHRISTIAN 2,916,807

HEAT EXCHANGE EQUIPMENT Filed Oct. 15, 1953 3 Sheets-Sheet '1 'I'I'IIII'IIIII'I'IIIIIII'IIIA I INVENTOR. JOSEPH D- CHE/.S'T/AN A MEMBER OF TH FIR I4 9 AT m BYM Dec. 15, 1959 Filed Oct. 15, 1955 J. D. CHRISTIAN HEAT EXCHANGE EQUIPMENT 3 Sheets-Sheet 2 7 Q uvmvrox. 0055/! a. CHRISTIAN ECKHOFF ucx BY' A MEMBIR F THE F! L Dec. 15, 1959 J. D. CHRISTIAN 2,916,807

HEAT EXCHANGE EQUIPMENT Filed Oct. 15, 1953 3 Sheets-Sheet 3 INVENTOR. JOSEPH D. CHRIST/AN ECKHOFF SLICK ATTORNEYS A MEMBER OF THE FIE United States Patent HEAT EXCHANGE EQUIPMENT Joseph D. Christian, San Francisco, Calif.

Application October 15, 1953, Serial No. 386,211

3 Claims. (Cl. 29-1563) This invention relates to heat exchange equipment.

In my prior patent, 2,321,185 of June 8, 1943, I disclosed a screw conveyor flight so constructed that a fluid could be passed through the flight in heat exchange relation to material in contact with the flight. That flight was provided by two helical flight members joined to the standard supporting the flight and to each other to provide a conduit for the heat exchange fluid. This device was utilized successfully for the heating and cooling of various materials. Later, I proposed the interleaving of two or more of such flights with adjacent flights driven in opposite directions; devices utilizing this latter construction have been used so successfully in the cooling or heating of many materials such as salt, flake caustic, cement and various other materials that handling methods and procedures for these have been revised and altered with advantage and saving to the particular industry.

The present invention is concerned with further improvements in such devices, particularly relating to the fabrication of the flights, their mounting upon the standard, improvements which enable the flights to be formed quite rapidly and, when completed, to be of such construction that the fluid conduit provided in each flight for the heat exchange fluid is one which will meet the various pressure vessel standards. Further, the flights can be readily ground and polished to provide smooth surfaces, even to a mirror-like finish, if this be desired.

It is in general the broad object of the present invention to provide an improved construction for a screw conveyor flight through which flight a heat exchange fluid can be circulated.

Another object of the present invention is to provide an improved construction for a heat exchange screw 0on v'eyor flight.

A further object is to provide a novel method for the formation of a heat exchange screw conveyor flight.

This invention includes other objects and features of advantage, some of which, together with the foregoing, will appear hereinafter wherein the preferred practice of the method of this invention and the preferred construction of the heat exchange screw conveyor flight are disclosed.

' In the drawing accompanying and forming a part hereof, Figure 1 is a side elevation partly in section through a heat exchange screw conveyor flight embodying the present invention.

Figure 2 is a section through another form of heat exchange screw conveyor flight embodying the present invention.

Figure 3 is a plan view of a disc from which a portion of the heat exchange screw conveyor flight is formed.

Figure 4is a plan view of the disc shown in Figure 3 during a further step in the manufacture.

Figure 5 is a section taken through the disc shown in Figure 4 along the line 5-5 thereof.

Figure 6 is a plan view of a disc at a further stage in its manufacture.

Figure 7 is a section taken along the line 77 in- Figure 6 thereof.

Figure 8 is a plan view of the disc shown in Figure 7,- illustrating diagrammatically where forming pressure is applied to the disc to form the helical flight.

Figure 9 is a perspective view of the helical flight after its formation.

Figures 10 through 14 are sections through a heat exchange screw, illustrating different embodiments of the invention.

Referring to Figure 3, the helical flight embodying this invention is formed as by providing an annulus such as that generally indicated at 6 having a central opening 9. The annulus is formed of any suitable material, usually a metal. As the next step in its manufacture, the annulus 6 is placed in a die and is subjected to such pressure application that the outer peripheral portion thereof, generally indicated at 7, is flared outwardly in one direction while the inner peripheral portion 8, adjacent to the central aperture 9, is flared in an opposite direction, as is shown in Figures 4 and 5. At this state of its manufacture, the annulus has been formed into a dish with the central portion provided with an extending neck.

Instead of flaring the outer and inner edges in opposite directions, both the outer and inner edges can be flared in the same direction (Figure 12), or the flaring can be confined to either the outer edge (Figure 14), or to the inner edge (member 26 in Figure 11); various flights illustrating such variations are shown in Figures 10 through 14.

In accordance with this invention, the disc is sheared radially as at 11 or a narrow radial slot 11 is cut in the disc extending from the inner aperture 9 to the periphery of the disc; the radial cut may be made in the annulus before it is bumped into a dish, but I prefer to make it after the deformation of the disc into the form of Figure 5.

In accordance with this invention, the thus-formed annulus'is then subjected to a deforming pressure by placing it between two dies having helically formed faces (See my Patent 1,748,206) to form the annulus into a helix having the desired helix angle. This is accomplished by applying the pressure only to that area indicated between the dotted lines 12 and 13 in Figure 8 and which lies intermediate the outer peripheral portion 7 and the inner peripheral portion 8. I have found that by applying the helical formation pressure to only this area, the flare provided upon the outer peripheral portion 7 of the annulus is not disturbed and the annulus can be formed into a strip having a uniform helix angle with the respective flared portion assuming the same angle; this is also true when the flare is provided on the inner peripheral portion 8 of the annulus adjacent to the opening 9. The helix-forming pressure is applied successively along the length of the annular member to form the helix.

A helix so formed is generally indicated at 14 in Figure 9. It will be noted that the flared portions extend uniformly and in their original directions and to their original extent, even though the whole has been provided with a definite and uniform helix angle. Usually, in forming the desired helix angle, the strip will be extended from its original circular length at 360 to an overall circular length of approximately 400. The initial outside diameter of the annulus and of the opening 9 are each slightly larger than those in the final flight for the deformation reduces these diameters.

The so-formed helix is then mounted upon a standard and in Figure 1, I have shown the completed helical flight 14 as mounted upon a pipe standard 16, in conjunction with a helical flight having a face 17 thereon extending radially at to the standard 16. Attention is, called. particularly. to. the. fact. that the flared portion 8 extends along the standard and that the welding indicated at 18, which joins the flared portion 8 to the standard, is. shown as tapered, the, junction of the flared portion 8 and the welding with the standardbeing smooth and continuous, In. this manner, a smooth-surface and joint is provided, one which will not retain 'any material which may be handled. This feature is-Of' particular advantage, for example, in the handling of various foodstuffs such as flour, tomato products, and the like, which may become subject to weavil contamination in the case of flour, or bacterial growth, in the case of tomato products. This feature is also of particular importance in the manufacture of various pharmaceutical materials, and cannot be over emphasized. For this reason, the flight 17 is flared as at. 21 and is joined by a smooth, continuous weld 22 to the standard.

In place of using the flight 14 in conjunction with a flight having a face extending radially at 90 to the standard, flight 14 can be used with a complementary flight of suitable hand, such as is indicated at 23 in Figure 2, so that both faces extend arcuately to the standard upon any radial axis at 90 to the standard. This last construction is of particular benefit in the provision of interleaved flights inasmuch as the use of these flights provides increased agitation as well as a higher ratio of heat exchange surfaceto unit volume of material in the device.

In Figures through 14, I have shown various hollow flights which can be fabricated within the teaching of-this invention; thus, in Figure 10, I have shown a hollow screw flight mounted upon the pipe standard 16 and including a first helical flight 24, extending radially at substantially 90 to the standard 16, and a second helical flight 14 which is arcuately formed in cross sec tion, being flared in its outer peripheral portion 31 in one direction and, in its inner peripheral portion 32 in an opposite direction. The hollow flight shown in Figure 11 is similar to that shown in Figure 10 except that the inner portion of flight 26 is flared inwardly as at 33. That form of flight shown in Figure 14 is similar to that shown in Figure 10 except that inner portion 34 of flight 1,4 is not flared but meets the standard 16 radially at substantially 90.

In that form of device shown in Figure 12, two helical flights 28 are flared in the same direction as at 36 and 37, the flights being welded to each other as at 38 and to the standard 16'as at 39. In that form of device shown in Figure 13, the hollow screw flight is made up of helical flights and 40; helical flight-30 is flared with outer portion 4-1 extending in the same direction as its inner portion 42, while flight 40 has its outer portion 43 extending in one direction and the inner portion 44 extending in a direction approximately 90 to the direction of the flare on portion 43;

In welding the flight in place on the standard, the latter is positioned horizontally, the flights tack-welded in place and then welded with plain flat fillet welds. This enables the welding to be effected with automatic'machines, if desired. That the present structure can' be assembled with automatic welding equipment is a feature of considerable importance, particularly in that this can be achievedwith the standard to which theflights are welded in a horizontal position. When the flights of my prior Patent 2,321,185 have been assembled with automatic Welding machines, it is necessary to incline the standard at a very steep angle and, as a consequence, a close pitch flight could not be manufactured. With the standard in a horizontal plane, this limitation is removed.

This is a continuation-in-part of my application Serial No. 323,571, filed December 2, 1952, now Patent No. 2,733,898.

I claim:

1. A method of manufacturing a section of hollow spiral conveyor comprising: forming a flat, annulus with a central hole therein; placing the said annulus in a die which leaves unsupported the outer peripheral portion of said annulus and applying pressure to such outer peripheral portion of said annulus to flare the said portion, sufficient pressure being applied that the outer peripheral flare describes, with the main body of the annulus, an angle of less than about and placing said annulus in a die which leaves unsupported the inner peripheral portion of said annulus and applying pressure to the said inner peripheral portion in a direction opposite to the direction of the outer peripheral flare whereby to flare the said inner peripheral portion; radially shearing the flanged annulus so formed from the outer periphery to the inner periphery thereof; placing the sheared annulus so formed between mating dies having helicallyformed faces and applying pressure by means of said dies only to non-flared portions of the said sheared annulus whereby to form said annulus into a helix without disturbing the flared peripheral portion; and thereafter welding the helical segment so formed to a mating helical segment, said weld being applied continuously along the outer peripheral edge of each segment and welding each of said segments to a supporting standard, the supporting standard weld being applied continuously at the:

point of juncture of the inner peripheral edge of each segment and the said supporting standard whereby to form a section of hollow spiral conveyor.

2. The method of claim 1 wherein the said helix-forming pressure is applied successively along the length of the said annulus.

3. The method of claim 1 wherein the said pressures are applied to each peripheral portion of the said annulus simultaneously while said annulus is supported in a die.

References Cited in the file of this patent UNITED STATES PATENTS 

